British Telecommunications Public Limited Company

Marc Wennink

Ben Strulo

Gabriele Corliano

Ben Sturlo

A method and system is described that adjusts the allocated capacity of a network between services, or service or traffic classes, in dependence on a congestion-influenced shadow price indication in respect of each service or class. In this respect, instead of viewing the congestion price as a cost of using already allocated unit of capacity, such a shadow price indication can be viewed as an indicator of the value obtainable from allocating an extra unit of capacity to a service or class. By so doing the shadow price indication becomes a factor to be taken into account in deciding on capacity allocation between services or classes, with a high shadow price indication for a service or class indicating that additional value would likely be obtained by allocating an additional unit of capacity to the service or class.

Capacity adaptation between services or classes in a packet network

A network has a plurality of edge nodes () and core nodes () for carrying flows of data from an ingress gateway () to an egress gateway () along a path of core nodes. For any given path in the network work from an ingress node to an egress node, the number of flows is controlled. When network congestion occurs, the egress gateway () provides an indication of the level of network congestion. Terminating flows is disruptive and therefore the ingress gateway () can mark other flows with a congestion marker and send them to the egress gateway (). These marked flows are routed by the core and egress gateway () but ignored for calculating network congestion. When the network congestion is alleviated, the marked flows can be un-marked and treated as normal flows, hence the network avoids unnecessary flow termination.

Network flow termination

Methods and systems for providing information relating to congestion at a network element caused by data units intended to be forwarded across a telecommunications network by the network element, the apparatus comprising: load-data receiving means for receiving load data relating to data units intended to be forwarded by the network element; rate-data obtaining means for obtaining data indicative of a configurable rate; first and second registers for storing first and second metrics; first and second updating means operable to update the metrics in said first and second registers in dependence on said load data and on the configurable rate; and a congestion indication provider operable to provide indications of congestion in dependence on the metrics stored in the registers; said apparatus being configured in such that it may provide behavior equivalent to a virtual queue marking scheme by virtue of a minor modification to hardware provided for Single Rate Three Color Marking.

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London, United Kingdom

Marc Wennink